A New Color Image Encryption Scheme Based on Chaotic Hénon Map and Lü System

Abstract

This paper presents a new efficient chaos-based color image cipher robust against chosen-plaintext attack. The chaotic Henon map and Lu system are employed to produce the permutation and substitution keystream sequences for image data scrambling and mixing, respectively. In the permutation stage, the positions of colored subpixels in the input image are scrambled using a pixel-swapping mechanism. To strengthen the robustness of the substitution procedure against chosen-plaintext attack, we introduce a novel mechanism for associating the keystream sequence with the plain-image. Compared with other related mechanisms, the new mechanism is implemented during the subpixel values mixing process rather than the keystream generation process. As a result, the keystream sequence can be reused among different rounds of substitution operation, and hence the computational cost is reduced. The suggested mechanism also increases the diffusion intensity and a desired diffusion effect can be achieved with only two rounds of overall permutation-substitution operation. Experimental results demonstrate that the proposed scheme has a satisfactory level of security.